Electrical tube



Sept. 15, 1931. c. QRSWELL 1,823,373

ELECTRICAL TUBE Original Filed June 23, 1926 Patented Sept. 15, 1931 I UNITED STATES PATENT OFFICE ISRAEL 0. ORSWELL, OF MEDFORD, MASSACHUSETTS, ASSIGNOR TO THE AMRAD COB- PORATION, OF MEDFORD, MASSAGHUSETTS, A CORPORATION OF OHIO ELECTRICAL TUBE Application filed .Tune 23, 1926, Serial No. 117,991. Renewed February 26, 1930.

The present invention relates to electrical tubes and more particularly to tubes operating through space conduction of electrical currents. Tubes of this general character 5 are of two types, the thermionic tube which operates through emission of electrons from a hot filament or cathode and the gaseous conduction tube which operates by ionization of molecules in a gaseous medium.

; One object of the invention is to provide a rectifier tube operating upon the principles of gaseous conduction by which there is obtained a high efficiency of rectification and auniform discharge over long periods of time. Another object of the present invention is to improve the construction of electrical tubes particularly with a view to providing a tube of rigid and durable construction in which the electrodes are supported in a man- :0 ner to be unaffected by mechanical stresses and to resist breakdown due to electrical discharges.

WVith the above and other objects in view as will hereinafter appear, one feature of the invention comprises a gaseous conduction tube having a cathode member of large internal surface surrounding an anode of comparatively small dimensions received within the cathode member, the electrodes being im- 0 mersed in a rarefied gaseous medium. With this construction, the tube possesses the property of unilateral conductivity, the current.

passing freely from the anode to the cathode, but not to an appreciable extent in the reverse direction. The construction of the present invention is such that considerable area for conduction at the surfaces of the electrodes is provided so that high current conduction without excessive heating or unduly large voltage drops is obtained. In the preferred form of the invention, the tube is constructed to give full wave rectification,

the cathode member for this purpose being divided into two parts by a central shield or 3 bafiie plate and the anodes being received in the opposite portions of the cathode member. The baffle plate forms an effective. portion of the cathode surface and by being extended beyond the anodes prevents undue electric discharge between the two anodes which are necessarily maintained at a high potential difference.

further feature of the invention consists in improved means for supporting the electrodes which may be employed for any type of tube, whether operating by gaseous ionlzation or by emission of electrons from a filament. The envelope is provided with a reentrant stem having at its u per end a press formed with a plurality o angularly disposed wings within which the lead-in wires and the supports for the electrodes are sealed. Ths angular arrangement of the wings provides for a rigid support of the electrodes at a number of spaced points, whlch not only assures a high resistance to deformatlon under mechanical stresses such as may be encountered in transit or in ordinary use of the tube, but also permits mountmg of the electrodes in a manner to localize the discharge, so that breakdown and nonuniform action are efiectively prevented.

Still further features of the invention conslst in certain novel features of construction, combinations and arrangements of parts hereinafter described and particularly defined in the claims.

In the accompanying drawings, Fig. 1 is a vertical elevation, partly in section, of a gaseous conduction tube embodying the several features of the present invention; Fig. 2 is a section on line 2-2 of Fig. 1; and Fig. 3 is a section on line 33 of Fig. 1.

The illustrated embodiment of the inventlon comprises a gaseous conduction tube adapted to give full wave rectification when connected into a suitable energizing circuit. The tube comprises a cathode and two anodes immersed in a gas which is preferably an inert gas such as helium under pressure of the order of magnitude of ten millimeters. The cathode member as shown is of cylindrical formation, being divided by a shield or baffle plate to form two cathode surfaces, and the two anodes are received within the two portions of the cathode, the entire assembly being supported upon a stem which is formed in a manner to give high mechanical rigidity and which is not affected by electrical stresses within the tube.

Referring particularly to the drawings, bushings in'order to protect the latter from the illustrated tube consists of a cathode memthe electric fields which are set up between the ber 2 which is of cylindrical formation, its two anodes. ends being joined by a seam indicated at 4. Electrical connections to the external cir- Cooperating with the cathode member are cuits are made through lead wires 40 and 42 two anodes 6 and 8 which are rod shaped and which connect tothe anodes and a wire 44 of materially less surface area than the which connects with the cathode member. cathode member. The anodes are received The lead wires 40 and 42 are welded to the within the cathode member, and protection lower ends of the anode wires before being against unduly large discharges directly besealed into the stem and the wire 44 is simitween the anodes is afforded by a shield or larly welded to one of the supporting wires bafile plate 10 which forms a part of the 26. The lead wires, as well as the supporting cathode member and which is welded there- Wires 26, are preferabl of copper-clad iron to at opposite sides. The shield divides the which may be convemently welded to the cathode member into two semi-cylindrical nickel electrodesand which form a tight seal cathodes and forms a portion of the cathode in cooperation with the glass stem. The ensurface of each. The shield is of greater velope is cemented to abase46whichhasaplulength than the c lindrical cathode member rality of contact pins 48 to which the various and extends consi erably above the upper exlead wires are soldered, as indicated in Fig. 1. tremities of the anodes so that the paths for The construction of the base and its associelectric discharge directly between the anodes ated contact pins is such as to permit engagearelong. Any discharge which takes place ment of the tube in any standard vacuum tube between the anodes, therefore, is unapprecisocket. able and does not materially affect the opera- The steps in the manufacture of the tube tion of the tube. The electrodes are of nickel, are briefly described as follows: The stem which has high heat resisting properties, and 14 of hollowcylindrical construction is first are immersed in a rarefied atmosphere of formed with a flare 50 at its lower end to afhelium or other inert gas contained in a ford connection to the envelope 12. The stem sealed'envelope 12. i is then suitably mounted for heating, at

The electrodes are supported in,the follow--which time the anode supporting tubes 28 ing manner: Connected with the envelope 12 and 30 are pressed in engagement with the at the bottom thereof is a re-entrant stem 14 stem while the supporting wires 26 for the which is formed at its upper end with a press cathode member and the anode wires 6 and indicated generally at 16. This press is 8 with their corresponding lead Wires are formed with four wings 18 of solid glass pressed in the proper position. The upper which extend at right angles to each other and end of the stem is then heated and is crimped which are of enlarged cross section at their to form the wings of the press, this action outer extremities, as indicated at-2O in Fig. 3. serving to unite the tubes 28 and 30 with the The wings are also enlarged along their upper press and at the same time to seal the various surfaces indicated at 22 in Fig. 1. These wires into the glass. The lava bushings are enlarged surfaces 22 constitute a thickened th n mounted on the anod and'the anodes l ge Which appears a in Fig-2. At e are bent as at 38 to retain the bushings in outer x ie o e c i g 1s sea ed a proper position. Next the cathode cylinder PP g bracket 26 Which i of is mounted on and welded to the supporting S form as to (image Wlth e lowe p bracketwires 26. The envelope 12 is then of the Cathode memhel The Cathode m msealed to the stem in the usual manner as the ber is welded to each of the bracket wires. t b i h t d th h th ti 52 A x- The anodes 6 and 8 eXteI 1d through glass ,haustion proceeds, the cathode member 2 is tubes 5 and 30 f p ya which are intensely heated by an induced high frerm gr l y Y h the e the aIIOde quency current to drive off any occluded gas. wlres themselves being sealed into the upper This heating is preferably carried to a point ledge P 24 0f the Stemc In Order to where the cathode member becomes white protect the glass tubes from discharges du hot. After the tube has been thus exhausted to the electrical stresses between the elecd i itt d t 1, th d i d amount trodes, e tubes are fitted ith bushings 32 of inert gas is admitted, whereupon the tube and 34 Whlch are of lava other lIlSlllatlIlg is sealed at the tip. The tube is then-mounted material. Each bushing has a recess which on the base, the lead wires being soldered fits closely over its cooperating glass tube and into the contact pins. h s t i upper end a en ral opening The supporting structure for the electrodes through which the anode wire extends. is applicable not only to a tube of the gase- After fitting of the bushings around the on". conduction type as illustrated and deanodes, the latter are bent as indicated at 38 scribed above, but may be used for supportin order to retain the bushings firmly thereon. ing the electrodes in a tube of any character,

It will be seen that the shield 10 extends for a as for example a tube of the thermionic type. slight distance below the bottom ends of the The formation of the press, with angularly disposed reinforced wings, presents high mechanical strength, which resists mechanical stresses applied in any direction. This stem, together with the supporting brackets for the cathode, forms a rigid and Mable structure which assures against deformation or relative displacement of the electrodes throu h stresses incident to handling or'use of t e tube. In the preferred form, the construction is such that electrical discharges are largely confined to the interior of the cathode member so that the possibility of continued discharges immediately adjacent to the walls of the tubeor of the stem are eflectively prevented. The tube,- therefore, is one of long life and uniform action, unaifectedby either mechanical or electrical stresses which may be encountered in ordinary use.

Having thus described the invention, what 39 is claimed is: I

1. An electrical tube comprising anenvelope, electrodes, and .a re-entrantstem formed with a press having a plurality of angularly disposed wings and a substantially flat top :5 portion connecting and surmounting the wings, supporting means for the electrodes and lead-in wires sealed in the press.

2. A rectifier tube comprising an envelope containing a gaseous medium, a cylindrical so cathode member, an anode, a re-entrant stemformed at its upper end with a press having a plurality of wings disposed at substantially right angles to each other and having a flat ledge portion surmounting the wings, a plurality of supporting members for the cathode sealed in the wings, and lead-in wires to the cathode and anode sealed in the press. 3. A rectifier tube comprising an envelope, a re-entrant stem formed with a press havo ing a plurality of angularly disposed wings,

anode tubes formed integrally with the stem, cathode supporting members sealed. in the wings of the press,a cathode mounted on the cathode supporting members, anodes extend- 4.5 ing through the anode tubes, and lead-in wires connected with the electrodes and sealed in the press. 7 In'testimony whereof I have signed my name to this specification.

5o ISRAEL 0; ORSWELL. 

